Truss construction



6, 1940- c. MACKINTOSH 2.210.460

TRUSS CONSTRUCTION Filed Aug. 1, 1939 INVENTOR.

ATTORNEY.

Patented Aug. 6, 1940 I UNI-TED?" STAT-ES PATE OFFICE 7 Claims.

"This inventionrelates to truss constructions and particularly to truss constructions of the type commonly made use of for supporting the roofs of building structures of various kinds, especially in certain commercial and industrial structures, where the distances between supporting Walls is sufliciently great to render the use of trusses necessary or advisable;

More particularly 'the invention relates to wooden trusses as distinguished from trusses fabricated of metallic members. Many roof supporting wooden trusses are used annually, these being usually of moderate length and most commonly employed for supporting the roofs of structures such as garages, stores, markets; factories, auditoriums, theaters, or the like. Generally speaking, however, the wooden truss as hereto: fore constructed has included important metallic members of special design such as a metal shoe, U-strap or similar connection, particularly to connect the ends of the upper and lower chords together. It will of course be appreciated that the ends of the upper chord of the roof truss'are rigidly attached to the ends 'ofthe lower chord ment of the ends of these two chords directly overlies the supporting wall or pillar. The means employed for rigidly securing together the ends of the upper and lower chords must be fully effective for the purpose intended, permitting no relative movements of the chords atthis point. Hence it has generally been deemed necessary to employ the relatively expensive and complicated. metallic attachment devices heretofore briefly referred to. These devices are quite efficient, but by reason of their special nature the cost of each truss which includes one or more of them, is substantially increased.

, While various efforts have been made heretofore to perfect a connecting member, or truss heel, of wood, which was at least the full mechanical equivalent of the metal connecting devices heretofore employed to secure rigidly to each other the ends of the top and bottom chords of wooden trusses, such efforts have for one reason or another not met with success. In ac cordance with the present invention, however, a wooden heel or connecting block consisting of one or more solid orlaminated pieces is actually made use of for this purpose, the ends of the top and bottom chords being so designed that a portion of the block is received within a recess formed in the lower chord and another portion of the block suitably engages the upper chord. The connecting block is so shaped and is so seand that in the general case the place of attach-- cured to each of the chords that the connection between the chords is extremely rigid, and likewise the connecting block in efiect forms portion of the lower chord in that its undersurface is adapted to bear upon the upper surface of a truss 5 seat such as a wall or pillar. The securing devices employed are simply metallic bolts of ordinary type used with or without timber connectors and are comparatively inexpensive, and a truss,

the chords of which are connected at their ends 10- in the manner specified, is not only rigid and durable but is considerably less expensive than other types in which theprincipal connecting means between the ends'of the chords comprise special metallic Shapes.

In the accompanying drawing certain forms of-the invention are illustrated, but it' will be understood that these embodiments are set forth by way of example only; and in adapting the invention for chords of various lengths and for go specific purposes, minor changes in the design and arrangement of its component elements may be made, without departing from the scope of the invention as defined by the subjoined claims.

In the drawing: i

Figure 1 is a diagrammatic representation of a truss of a type which may advantageously embody the invention;

Figure "2 is a side elevation, on a much larger scale, of one end of the truss shown in Figure 1, showing the junction between the upper and lower parts;

Figure'B is an end in Figure 2; v

Figure 4 is a perspective view of one of the connection blocks which may be used;

Figure 5 is a section on line 55 of Figure 2;

Figure 6 is a section taken at the same point and illustratinga use of timber connectors in the trust construction;

Figure 7 is a similar section'showing a modified top chord construction; and

Figure 8 is a fragmentary view in perspective of still another form of connection, theheel block and the upper chord being separated for the purposes of better illustration.

The truss shown in Figure 1 includes a continuously curved upper chord, but it will be appreciated that the upper chord need not necessarily be curved and that the chord ends of wooden trusses of numerous other types and designs may be connected in the novel manner about to be described.

The lower chord of the truss is generally indicated at H! and the upper chord at H, these elevation of the truss shown chords being angularlydisposed in the customary manner. The lower chord W is provided with a recess in its end to receive the connection block l2, shown in perspective in Figure 4. The recess in the lower chord, l provided for the reception of the block or heel l2 may either comprise a vertical slot or notch formed in the end of a solid chord, or it may comprise a vertical space between two parallel members such as M and 15, disposed vertically and suitably secured together so as to act as one member. The undersurface of the connecting block I2 is preferably, although not necessarily, flush with the undersurfaces of the members l4 and I5 so that these three surfaces form in effect one continuous surface which rests upon the top of a truss seat It, which may be portion of a wall, or top of a pillar. Block I2 is rigidly secured in the position in which it is shown by means of bolts H which extend horizontally through aligned apertures in the members [4 and i5 and block HQ.

The upper chord H in the embodiments shown in. Figures 1 to" 7 inclusive comprises several members, such, for instance, as the top member i8 and the vertical parallel members l9 and 2B towhich the top member I8 is rigidly attached. Where the upper chord includes parallel vertical members such as indicated at 69 and 20, the end surfaces of these members abut against the inclined face !2a of block l2 and lie upon opposite sides of the tongue l2?) which is an integral part of the heel i2 and extends therefrom upwardly at an inclination, as shown most clearly in Figure 4. A securing bolt 22 passing through aligned apertures in the vertical members l9 and 20 in the tongue I22) rigidly attaches members l9 and 28 to the block I2. Securing bolts 23 and 24 serve to attach rigidly the top member f8 of the upper chord'to the connection block or heel 12.

The extreme lower end of the top member H! of the upper chord projects downwardly .into the recess intermediate webs I4 and I5, and as clearlyv shown at 25, thus providing an additional lateral support for the upper .chord.

As shown in Figure 6 of the drawing, the various bolts such as I1, 22, 23 and 24 may be augmented by timber connector elements of known types, such as the so-called split rings shown at 26, these rings having annular flanges which enter similarly formed grooves in the adjacent surfaces of the wooden members. It will be appreciated that the application of these rings will in all cases be similar to that illustratedin connection with bolts 22.

When unusually high compressional stresses to come upon the top chord, it may be desirable to add a member 2'! which lies under the tongue Rb and parallel to the member 18, as illustrated in Figure 7 of the drawing. It will be appreciated by those skilled in the art that the top member l8 and/or the bottom member 2'! may be made integral with the members i9 and 29 and also that the members 19 and 213 or the members l8 and 21 may be integral, above or beyond the tongue l2b of the block l2, if

desired. For example,'in Figure 8 there is shown a solid upper chord member II! which is provided with a socket Illa which is adapted to receive the tongue or tenon member I Hi) formed on the heel block I I2 and analogous to the tongue 52b of the preceding embodiments, the end of the chord H l abutting the inclined surface 211 of the block.

The invention is susceptible of very consider able modification, but in every instance the upper chord will at its outer end be associated with the upper portion of the connecting block and the end of the lower chord will be slotted or recessed for the reception of this block. With such construction extreme rigidity is realized, even though the securing devices employed are simply bolts with or without conventional timber connector piece 26. Y

The truss construction described is of great simplicity and may be readily assembled in the shop or in the field. Itis extremely rugged and durable and is much less costly than the generally similar truss constructions now on the market.

Having thus describedthe invention, what is claimed as new and desired to be secured by Letters Patent is:

1. A roof truss construction comprising an upper chord, a lower chord, and a connecting block, the end of saidlower chord having a recess opening upwardly for the reception of said block, said block extending above said lower chord and into engagement with the end of said upper chord, and means rigidly securing both said chords to said block.

2. The combination set forth in claim 1 in which a portion of the upper chord extends into the recess formed in the lower chord.

3. The combination set forth in claim 1 in which the upper chord includes an element which overlies theconnecting block and an element the end surface of which seats against the block.

1. The combination set forth in claim 1 in which the upper chord includes spaced vertical mmebers the end surfaces of which bear against the connecting block and the connecting block includes a tongue which lies intermediate said members and is secured thereto.

5. The combination set forth in claim 1 in which the recess in the lowerchord also opens downwardly and the lower surface of the connecting block is adapted to bear upon the upper surface of a connecting wall or pillar.

6. The combination set forth in claim 1 in which the connecting blockincludes aprojecting tongue and the end of the upper chord includes vertical and horizontal portions which surround said tongue upon all sides.

7. The combination set forth in claim 1 in which the connecting block includes a projecting tongue and. in which the upper chord is solid and is provided at'its end with a mortise shaped to receive the tongue of said block.

CHARLES MACKINTOSH. 

